1. Field of the Invention
The present invention relates to a rotor for a rotating electrical device and more particularly to a rotor in which a rotor coil is wound and disposed for a rotating electrical device.
2. Description of Related Art
Some rotating electrical devices have a rotor structure in which the rotor coil is wound and disposed in the rotor. For example, Japanese Patent Application Publication No. 2009-112091 (JP 2009-112091 A) discloses a structure of a rotating electrical device in which multiphase alternating current is applied to multiphase stator coils to generate a rotating magnetic field on a stator, and a space harmonic component of the rotating magnetic field is interlinked with rotor coils to generate induced current on a rotor coil. In JP 2009-112091 A, the rotor coils are respectively wound on rotor salient poles of the rotor, and diodes establish short circuits in the respective rotor coils to rectify the induced current. Thus, each rotor salient pole is magnetized with desired polarity, and desired magnetic pole of the rotor can be achieved. In this way, north poles and south poles are alternately formed on the rotor salient poles. Accordingly, the rotor salient poles interact with the rotating magnetic field on the stator, and torque acts on the rotor.
It is desired in the rotor for the rotating electrical device disclosed in the aforementioned JP 2009-112091 A that the rotor coils wound on the rotor salient poles be prevented from falling out due to centrifugal force, while the loss in a case where magnetic flux saturation does not occur in the rotor salient pole is reduced during low-load conditions. It is also desired that ease of assembly of the rotor coil be improved.